The present invention relates generally to a label identification system and more particularly to a capacitive label identification system for use in remote locations.
The storage of Special Nuclear Material (SNM) such as uranium or plutonium has special problems not usually associated with the storage of large quantities of precious metal. For instance, because of the potential for contamination, SNM must be sealed in air-tight containers that are reasonably small to avoid the problem of critical mass. One common container that has been found useful for this purpose is the 46 ounce foodpack can, a container more often used for retail distribution of tomato juice. For SNM, these containers carry an identification label and a frangible plastic or paper seal. The containers are kept in a vault for physical security, and must be periodically inventoried to maintain accountability of the SNM. A random sample of containers are opened for an actual material verification. Since these cans do not provide shielding for the radiation of the material contained therein, the accountability procedure absorbs much of the allowable safe-exposure limit for the custodial personnel; and, because of the long interval between inventories, does not provide the real-time accountability needed to help deter theft.
A previous system considered for use at one Department of Energy SNM storage facility utilizes limit switches to provide electrical signal indications that a can is at a location and that the can is not bulging (an indication that impurities in the SNM may cause the can to rupture). However, no current system permits a remote monitoring of the identity of a particular can at a particular location.